The invention relates to an apparatus for gripping and decollating the bottom blank of a stack of blanks and is especially useful in a book covering machine.
Devices of this type are known (e.g., see a book covering machine BDM 20 of the Horauf Maschinenfabrik GmbH & Co. KG, Donzdorf, West Germany). In this known machine a supporting surface supports a stack of book cover blanks. The surface includes a recess which enables a suction grip to act on the bottom blank. A stop is oriented perpendicularly to the stop for abutting one end of the stack. The reason for orienting the stop perpendicularly to the supporting surface is that it has been assumed as a rule that the end of the stack is parallel to the plane of the supporting surface. This, however, is not true if, for example, the blanks are lacquered on their top side. In such a case the individual blanks, and therefore the entire stack, are bent so as to curve upward, so that the end of the stack is inclined relative to the stop, as depicted in FIG. 3. The bottom blank can then no longer be gripped and decollated with the usual amount of vacuum of the suction grip.
It is, therefore, an object of the invention to eliminate this disadvantage and to provide an apparatus of the aforementioned type wherein even a bent stack of blanks may be safely gripped and decollated in the aforedescribed manner.